All cloud types
Cloud Name
Cumulonimbus
A huge tower cloud that can bring heavy rain, lightning, strong gusts, and sudden rough conditions.
What it looks like
Cumulonimbus clouds grow very tall, often with a dark base and a spreading anvil-shaped top. They are the classic thunderstorm clouds.
Simple meaning
This cloud means the weather can change fast. Expect strong wind gusts, heavy rain, lightning, and poor visibility.
For boating
Avoid open water if possible. Reef early, watch radar, and prepare for squalls, lightning, and steep short waves.
How to recognize Cumulonimbus
- Very tall cloud towers
- Dark base
- Anvil-shaped top
- Heavy showers or lightning nearby